Pet food comprising trisodium L-ascorbic acid-2-monophosphate or sodium-calcium L-ascorbic acid- 2-monophosphate, or mixtures thereof and, optionally, a polymer and use 5 thereof as additive to pet food for preventing or treating calculus, plaque, gingivitis and periodontal disease and for enhancing the antioxidative capacity in the whole organism. The method provides a transparent substrate, such as quartz, with a surface. The method further comprises transcoding the first compressed version to a second compressed version compressed using a second compression method that is in relatively widespread use.